1,3-Propanediol production from crude glycerol by Clostridium butyricum DSP1 in repeated batch

AbstractBackgroundThe production of biofuels from renewable energy sources is one of the most important issues in industrial biotechnology today. The process is known to generate various by-products, for example crude glycerol, which is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol (1,3-PD), a raw material for the synthesis of polyesters and polyurethanes.ResultsThe paper presents results of a study on the synthesis of 1,3-propanediol from crude glycerol by a repeated batch method with the use of Clostridium butyricum DSP1. Three cycles of fermentation medium replacement were carried out. The final concentration of 1,3-PD was 62g/L and the maximum productivity, obtained during the second cycle, reached 1.68g/L/h. Additionally, experiments conducted in parallel to the above involved using the entire quantity of the culture broth removed from the bioreactor to inoculate successive portions of fermentation media containing crude glycerol at concentrations of 80g/L and 100g/L. Under those conditions, the maximum 1,3-PD concentrations were 43.2g/L and 54.2g/L.ConclusionsThe experiments proved that by using a portion of metabolically active biomass as inoculum for another fermentation formula it is possible to eliminate the stage of inoculum growth and thereby reduce the length of the whole operation. Additionally, that strategy avoids the phase of microbial adaptation to a different source of carbon such as crude glycerol, which is more difficult to utilize, thus improving the kinetic parameters of 1,3-PD production

Essays on rational asset pricing

Essays on Rational Asset Pricing is a collection of essays demonstrating the ability of rational asset pricing theory to explain differences in expected returns across assets. The first two essays analyze the cross-sectional and time-series predictability of returns on commodity futures contracts. Historically, futures have earned average returns similar to those of equities. Nevertheless, they fulfill a different economic function. We find that expected futures returns vary in a systematic way due to differences in consumption risk, similar to the returns on stocks. However, unlike for stocks, demand and supply changes which are related to commodity prices - and therefore consumption - lead short run consumption risk to be important for explaining commodities’ returns but not long run consumption risk. In the third essay, we extend the analysis on predictability by showing how restrictions imposed by asset pricing theory on the measures of predictability change when investors face short sale constraints and transaction costs. Finally, in the last essay we relax the assumption of rational pricing and allow for behavioral biases on the side of the investor to explain mispricing observed in a particular class of securities, reverse convertible bonds.

Essays on Rational Asset Pricing.

Essays on Rational Asset Pricing is a collection of essays demonstrating the ability of rational asset pricing theory to explain differences in expected returns across assets. The first two essays analyze the cross-sectional and time-series predictability of returns on commodity futures contracts. Historically, futures have earned average returns similar to those of equities. Nevertheless, they fulfill a different economic function. We find that expected futures returns vary in a systematic way due to differences in consumption risk, similar to the returns on stocks. However, unlike for stocks, demand and supply changes which are related to commodity prices - and therefore consumption - lead short run consumption risk to be important for explaining commodities’ returns but not long run consumption risk. In the third essay, we extend the analysis on predictability by showing how restrictions imposed by asset pricing theory on the measures of predictability change when investors face short sale constraints and transaction costs. Finally, in the last essay we relax the assumption of rational pricing and allow for behavioral biases on the side of the investor to explain mispricing observed in a particular class of securities, reverse convertible bonds.

Sukcesja państw po rozpadzie Socjalistycznej Federacyjnej Republiki Jugosławii

The Socialist Federal Republic of Yugoslavia ceased to exist in 1991, though some topics concerned with the succession of its constituent states were not regulated for a long time afterwards. This issue and the efforts to solve it were examined by the Arbitration Commission of the Peace Conference on the former Yugoslavia. When answering all the related questions, the Arbitration Commission used as a basis the 1978 Vienna Convention on the Succession of States in respect of Treaties and the 1983 Vienna Convention on the Succession of States in respect of State Property, Archives and Debts. The final solution to the problem of SFRY succession was found in 2001 when the Agreement on Succession Issues was signed, although it came into force three years later. There were no problems with the succession of citizenship. Under the 1974 Constitutional Act of SFRY, there were two citizenships in the federation – federal and republican. Therefore, after the breakup of Yugoslavia, republican citizenship became the citizenship of a new state

Phyllotactic patterns in capitula of Carlina acaulis L.

Phyllotaxis of inflorescences in Car/ina acaulis L. is spiral. In the majority of capitula it is represented by the main Fibo­nacci series. From the one thousand of specimens, thai were examined, thirty five new phyllotactic series were found: eighteen monojugies, for instance (2,17), (4, 11), (7,37) and seventeen multijugies, such as 2(8,9), 2(5,11), 8(2,3). The patterns had been identified on the basie of two or more consecutive num bers of phyllotaclic series. Both, the continuous and discontinous trans­formations of phyllotactic patterns, as well as 'deviations' from the parastichy group numbers were observed. The deviations were distinguished as the probable cases of the discontinuous transformations in which the sectorial change in the parastichy number occured, but the ultimate phyllotactic series could not be determined

The diagram for phyllotactic series

Many authors studying phyllotaxis in various plant species have reported the occurrence of many different numbers of contact parastichy pairs that are members of different Fibonacci-like series. On the basis of these reports a diagram was constructed in which any theoretically possible series was represented by the two first members of a given series

Asset Pricing Restrictions on Predictability

U.S. stock portfolios sorted on size, momentum, transaction costs, M/B, I/A and ROA ratios, and industry classication show considerable levels and variation of return predictability, inconsistent with asset pricing models. This means that a predictable risk premium is not equal to compensation for systematic risk as implied by asset pricing theory (Kirby 1998). We show that introducing market frictions relaxes these asset pricing moments from a strict equality to a range. Empirically, it is not short sales constraints but transaction costs (below 35 basis points) that help to reconcile the observed predictability with the Fama-French-Carhart four- factor model and the Chen-Novy-Marx-Zhang three factor model, and partly with the Durable Consumption model. Across the sorts, predictability in industry returns can be reconciled with all models considered with only 25 basis points transaction costs, whereas for momentum and ROA portfolios up to 115 basis points are needed

Various scenarios of the cell pattern formation in Arabidopsis lateral root

During lateral root (LR) development a coordinate sequence of cell divisions, accompanied by a change of the organ form takes place. Both the order of anatomical events and morphological features may vary for individual primordia. At early stages of LR primordia development oblique division walls are inserted in cells that are symmetrically located on both sides of the axis of the developing LR primordium, and thereby allow for the protrusion of the LR. We hypothesize that both oblique cell wall insertion and continuous changes in primordium form could be a consequence of a local change in stress distribution in the region of the LR initiation

On the choice of thickness of the cement mantle in cemented hip arthroplasty

Recommendations for the optimal thickness of the cement mantle in cemented hip arthroplasty are outlined based on the results obtained with the finite element method. The investigations show that distal femur cement thickness higher than 2 mm positively affects mechanical behaviour of the cement mantle and can be useful in reducing stress-strain levels in the distal part of the femur what leads to prevention of development of a stress-shielding effect. The results of the study can contribute to the success of long-term implants